I agree on the taxis. Too much left to chance.
Imagine if, instead of the whole Voodoo Donuts thing, the team could have been instructed to find a west-bound light rail train to Washington Park, get off in the tunnel station, take the elevator up to the park, and then run the two miles or so through the forest to the Pittock Mansion using the somewhat primitive mapboard to get there.
And imagine if they could have been required to look for a clue in the Chinese Garden downtown or in the Japanese Garden in Washington Park.
Lots of missed opportunties.